Fossil fuel combustion is an important source of power generation, and provides a major portion of the world's power demands. Unfortunately, fossil fuel combustion is also a major contributor of pollutants to the atmosphere and environment. The exhaust gases that result from burning fossil fuels, called “flue gases,” contain many harmful air pollutants, such as nitrogen oxides, sulfur dioxide, carbon dioxide, volatile organic compounds and heavy metals.
Various environmental regulations mandate treatment of flue gas, such as sulfur dioxide (SO2) and carbon dioxide (CO2) capture and removal. These treatment processes can greatly increase the cost of power production, resulting in higher prices to the consumer. Improved techniques, processes, and devices for treating flue gases help to control and reduce the increasing costs of power production.
U.S. Pat. No. 7,255,842 to Yeh teaches a process for removing sulfur oxides, nitrous oxides, and carbon dioxide from flue gases without producing harmful byproducts and while achieving low energy consumption. While Yeh appreciates the need to reduce operational costs, Yeh fails to appreciate that the net costs of building, operating, and maintaining a power plant can be lowered despite a moderate raise in operational costs. Of particular importance to the present application, Yeh fails to appreciate that a single fan system consuming high amounts of energy can actually reduce overall costs compared to a system that utilizes two fans that consume a lower amount of energy than the single fan.
There is still a need for improved processes and systems for post-combustion treatment of flue gases that reduce the net costs of power production.